Aren't there homogeneous states in the U.S.? I believe it has been shown that for similar cities, the U.S. system is worse - I think I saw an example of an U.S

Aren't there homogeneous states in the U.S.? I believe it has been shown that for similar cities, the U.S. system is worse - I think I saw an example of an U.S. and a Canadian city across the border, similar demographics, the U.S. one had 10 times the crime rate, etc..